Chain Guide Zero-Touch Surface for Low-Friction Vibration Control

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Solution Overview

Problem

Existing chain guides in timing chain transmission devices generate significant frictional resistance and energy loss due to extensive sliding contact with the chain, leading to abnormal noise, wear, and vibration issues, as seen in PTL 1 and PTL 2, where reduced contact areas result in intermittent contact and variable load-induced string vibration.

Innovation Solution

A chain guide with two shoe portions for contact and a vibration control portion having a zero-touch surface along the chain's travel line, reducing contact area and frictional resistance, while preventing string vibration by maintaining minimal contact with the chain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the chain guide is in sliding contact with substantially an entire region of the tension-side chain, then the chain is guided stably, but frictional resistance increases and energy loss increases

Engineering Contradiction:

Improvechain guidance stabilityVSAvoidenergy loss

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The chain guide is divided into multiple contact portions (first contact portion, second contact portion, third contact portion) along the chain travel direction, with non-contact portions between them. This segmentation reduces the total contact area while maintaining guidance stability through distributed contact points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the chain guide have different contact characteristics - contact portions provide guidance and support, while non-contact portions reduce friction. The guide groove bottom surface has locally varied properties with alternating contact and non-contact zones.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If the contact area between the chain guide and the chain is reduced, then frictional resistance is reduced, but the chain abuts against the convex portions intermittently and abnormal noise is generated

Engineering Contradiction:

Improvefrictional resistanceVSAvoidabnormal noise

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The guide groove bottom surface is segmented into convex portions and concave portions, creating multiple small contact areas rather than one large contact area. This distributes the chain load and prevents intermittent slapping sounds.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The convex and concave portions are formed with curved surfaces that match the chain link geometry, allowing smooth contact and reducing impact noise compared to sharp edges or flat surfaces.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Loss of energy

If the contact area is reduced to reduce frictional resistance, then energy loss is reduced, but contact pressure increases and the chain guide is worn away at an early stage

Engineering Contradiction:

Improvefrictional resistanceVSAvoidchain guide durability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The contact area is divided into multiple segments (convex and concave portions) that distribute the chain load. This reduces contact pressure at each individual contact point while maintaining adequate total support, preventing premature wear.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The guide groove has locally optimized surfaces - convex portions for contact and concave portions for oil retention. The synthetic resin material properties are leveraged to provide self-lubrication and wear resistance at contact points.

Inventive Principle:

Principle #3Local quality

4Volume of moving object

If a non-contact portion with an opening portion is formed between contact portions, then the gap between the chain and engine block is reduced, but the chain travels in a non-contact manner without being guided and string vibration occurs

Engineering Contradiction:

Improvetiming chain compactnessVSAvoidchain guidance stability

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The chain guide structure is segmented into contact and non-contact portions, allowing the chain to be guided at discrete points while maintaining compactness. The non-contact portions create gaps that reduce the overall envelope size.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of continuous contact guidance, partial contact at specific portions is sufficient to guide the chain. This partial action approach maintains guidance stability while enabling a more compact design.

Inventive Principle:

Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly reduces frictional resistance by 10% or more, minimizes energy loss, and prevents abnormal noise and wear, ensuring stable power transmission and accurate timing over extended periods.

Implementation Method 1

a vibration control portion having a zero-touch surface extending along a travel line of the chain

Methodology Applied

Scientific EffectVibration control: Vibration

Implementation Method 2

a contact guide portion configured to come into contact with a chain and guide the chain

Methodology Applied

Scientific EffectFriction reduction: Friction

Data Source

PatentUS11927267B2Chain guide and chain transmission device using same

Publication Date: 2024.03.12 DAIDO KOGYO CO LTD

AI summary

A chain guide includes a contact guide portion that comes into contact with a chain and guides the chain, and a vibration control portion having a zero-touch surface extending along a travel line of the chain.